using iTextSharp.text;
using iTextSharp.text.pdf;
using System;
using System.IO;

namespace ReportEngine
{
    public class ReportCanvas : PdfPageEventHelper
    {
        PdfContentByte _dcContent;
        PdfTemplate _tFooterPageTotal;

        readonly ReportCanvasOptions _rpoOptions;
        public ReportCanvas(ReportCanvasOptions i_rpoOptions)
        {
            _rpoOptions = i_rpoOptions;
        }

        public override void OnEndPage(PdfWriter writer, Document document)
        {            
            // 頁尾頁數設定
            if (_rpoOptions.IsShowPageNumber)
            {
                var baseCenter = _rpoOptions.PageSize.Right / 2;
                var pageBottom = (document.BottomMargin - _rpoOptions.FontSize) / 2 + 5;
                var pageCenter = baseCenter;   // 頁碼偏移
                var pageN = writer.PageNumber;
                string pageText = $"{pageN}/" ;
                var textWidth = _rpoOptions.BaseFont.GetWidthPoint(pageText, _rpoOptions.FontSize);
                _dcContent.SetFontAndSize(_rpoOptions.BaseFont, _rpoOptions.FontSize);   // 預設文字大小
                _dcContent.BeginText();
                _dcContent.ShowTextAligned(PdfContentByte.ALIGN_LEFT, pageText, pageCenter- textWidth, pageBottom, 0);
                _dcContent.EndText();
                _dcContent.AddTemplate(_tFooterPageTotal, pageCenter, pageBottom - 1);
            }

            base.OnEndPage(writer, document);

        }

        public override void OnOpenDocument(PdfWriter writer, Document document)
        {
            base.OnOpenDocument(writer, document);
            _dcContent = writer.DirectContent;

            if (_rpoOptions.IsShowPageNumber)
            {
                _tFooterPageTotal = _dcContent.CreateTemplate(50, 50);
            }
        }

        public string Paint(Func<ReportPainter, ReportCanvasOptions, string> i_fPainting,
            [System.Runtime.CompilerServices.CallerLineNumber] int i_nCodeLine = 0,
            [System.Runtime.CompilerServices.CallerMemberName] string i_sMemberName = "",
            [System.Runtime.CompilerServices.CallerFilePath] string i_sSourcePath = "")
        {
            string sMsg;


            try
            {
                do
                {
                    
                    Document doc = new Document(_rpoOptions.PageSize,
                        _rpoOptions.PageMarginLeft,
                        _rpoOptions.PageMarginRight,
                        _rpoOptions.PageMarginHeader,
                        _rpoOptions.PageMarginFooter);

                    MemoryStream memoryStream = new MemoryStream();
                    PdfWriter writer = PdfWriter.GetInstance(doc, memoryStream);

                

                    writer.CloseStream = false;

                    if (_rpoOptions.UserEntercode != null && _rpoOptions.OwnerEntercode != null)
                    {
                        writer.SetEncryption(PdfWriter.STRENGTH128BITS, _rpoOptions.UserEntercode, _rpoOptions.OwnerEntercode, PdfWriter.AllowPrinting);   // 設定PDF權限
                    }
                    writer.PageEvent = this;   // 頁首頁尾設定

                    ReportPainter rp = new ReportPainter(doc, _rpoOptions, writer);


                    doc.Open();
                    sMsg = i_fPainting.Invoke(rp, _rpoOptions);

                    if (sMsg != null)
                    {
                        break;
                    }

                    doc.NewPage();

                    // 沒有資料時顯示文字
                    if (writer.PageNumber == 1)
                    {
                        rp.WriteText("無資料");
                    }
                    doc.Close();

                    using var fs = new FileStream(_rpoOptions.OutputPath, FileMode.OpenOrCreate, FileAccess.Write);
                    memoryStream.Seek(0, SeekOrigin.Begin);
                    memoryStream.CopyTo(fs);
                }
                while (false);
            }
            catch 
            {                
                sMsg = $"{nameof(Paint)} unknwon exception. Call from {i_sMemberName} {i_sSourcePath}({i_nCodeLine}).";
#if DEBUG
                System.Diagnostics.Debug.WriteLine(sMsg);
#endif 
            }
            return sMsg;
        }

        public override void OnCloseDocument(PdfWriter writer, Document document)
        {
            base.OnCloseDocument(writer, document);

            // 顯示每個頁碼的總頁數(僅此處可抓到)
            if (_rpoOptions.IsShowPageNumber)
            {
                _tFooterPageTotal.BeginText();
                _tFooterPageTotal.SetFontAndSize(_rpoOptions.BaseFont, _rpoOptions.FontSize);
                _tFooterPageTotal.ShowTextAligned(PdfContentByte.ALIGN_LEFT, (writer.PageNumber - 1).ToString(), 0, 1, 0);
                _tFooterPageTotal.EndText();
            }
        }
    }
}